Malaria Journal BioMed Central Research Open Access Plants traditionally prescribed to treat tazo (malaria) in the eastern region of Madagascar Milijaona Randrianarivelojosia*1, Valérie T Rasidimanana1, Harison Rabarison2, Peter K Cheplogoi3, Michel Ratsimbason4, Dulcie A Mulholland3 and Philippe Mauclère1 Address: 1Groupe de Recherche sur le Paludisme, Institut Pasteur de Madagascar BP 1274, Antananarivo (101) Madagascar, 2Conservation International Madagascar, BP 5178 Antananarivo (101) Madagascar, 3Natural Products Research Group, School of Pure and Applied Chemistry, University of Natal, Durban, South Africa 4041 and 4Centre National d'Application des Recherches Pharmaceutiques BP 702, Antananarivo (101) Madagascar Email: Milijaona Randrianarivelojosia* - [email protected]; Valérie T Rasidimanana - [email protected]; Harison Rabarison - [email protected]; Peter K Cheplogoi - [email protected]; Michel Ratsimbason - [email protected]; Dulcie A Mulholland - [email protected]; Philippe Mauclère - [email protected] * Corresponding author Published: 24 July 2003 Received: 24 June 2003 Accepted: 24 July 2003 Malaria Journal 2003, 2:25 This article is available from: http://www.malariajournal.com/content/2/1/25 © 2003 Randrianarivelojosia et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are per- mitted in all media for any purpose, provided this notice is preserved along with the article's original URL. Abstract Background: Malaria is known as tazo or tazomoka in local terminology in Madagascar. Within the context of traditional practice, malaria (and/or malaria symptoms) is commonly treated by decoctions or infusions from bitter plants. One possible approach to the identification of new antimalarial drug candidates is to search for compounds that cure or prevent malaria in plants empirically used to treat malaria. Thus, it is worth documenting the ethnobotanical data, and testing the antiplasmodial activity of the extractive from plants. Methods: We interviewed traditional healers, known locally as ombiasy, at Andasibe in the eastern, rainy part of Madagascar. We recorded details of the preparation and use of plants for medicinal purposes. We extracted five alkaloids from Z. tsihanimposa stem bark, and tested them in vitro against Plasmodium falciparum FCM29. Results: We found that traditional healers treat malaria with herbal remedies consisting of one to eight different plants. We identified and listed the medicinal plants commonly used to treat malaria. The plants used included a large number of species from different families. Zanthoxylum sp (Rutaceae) was frequently cited, and plants from this genus are also used to treat malaria in other parts of Madagascar. From the plant list, Zanthoxylum tsihanimposa, bitter plant endemic to Madagascar, was selected and examined. Five alkaloids were isolates from the stem bark of this plant, and tested in vitro against malaria parasite. The geometric mean IC50 values ranged from 98.4 to 332.1 micromolar. The quinoline alkaloid gamma-fagarine exhibited the strongest antiplasmodial activity. Conclusions: The current use of plants for medicinal purposes reflects the attachment of the Malagasy people to their culture, and also a lack of access to modern medicine. The possible extrapolation of these in vitro findings, obtained with plant extracts, to the treatment of malaria and/or the signs evoking malaria is still unclear. If plants are to be used as sources of novel antimalarial compounds, we need to increase our knowledge of their empirical use to improve plant selection. In the hope of preserving useful resources, we should now gather and record ethnobotanical data in Madagascar, and should try to bridge the gaps between empirics and realism. Page 1 of 9 (page number not for citation purposes) Malaria Journal 2003, 2 http://www.malariajournal.com/content/2/1/25 Background have lead to artificial responses, given purely to satisfy the Malaria, which was initially recognized as episodic fever, researcher. was probably introduced into Madagascar from mainland Africa by immigration. Malaria was reported as early as We obtained from these healers information relating to 1602 on the coast of Madagascar [1]. This disease remains the identification of plants, their medicinal uses and the a public health problem [2]. The Malagasy words tazo and preparation of remedies. We focused particularly on the tazomoka refer to the clinical signs suggestive of malaria: information provided concerning the plants used to treat principally fever, headache, backache, shivering and tazo (malaria). There was considerable overlap between fatigue. Malagasy people, particularly those living in the the information obtained from the three healers concern- countryside, use traditional plants to fight infectious dis- ing the plants and treatments used. We, therefore, simply eases. The current use of plants for medicinal purposes generated a combined pharmacopea for the three healers. reflects the attachment of the people to their culture and a The forester we worked with identified the plants from the lack of access to modern medicine (associated with pov- given vernacular names. Samples were taken for all the erty in most cases). plants listed, which were then compared with the type specimens from the National Park Herbarium, to ensure Local people are confident that they can recognize the accurate identification. signs of malaria http://www.pasteur.mg/AtlasPalu/ pdspalu.htm. Within the context of traditional practice, The "principal" plants used as antimalarial which were malaria and/or malaria symptoms are treated by decoc- cited independently by at least two of the three healers tions or infusions from bitter plants. Examined bitter interviewed were listed by family and in alphabetical plants reported to have traditionally antimalarial proper- order (see plant list). We give both the scientific name of ties usually contain bitter compounds such as alkaloids, plant and the vernacular name, in that order. The list of limonoids or quassinoids [3–7]. "secondary" plants which may be mixed with the "princi- pal" one is also added. The resistance of Plasmodium spp. to drugs – such as chlo- roquine – has become a serious problem in areas of Chemical analysis and in vitro antimalarial testing endemic malaria and in malaria-free areas with occasional In targeting plants which might contain antimalarial com- imported cases. One possible approach to the identifica- pounds, attention was focused on the plants used to make tion of new antimalarial drug candidates is to search for infusions and decoctions to treat malaria. Zanthoxylum tsi- compounds that cure or prevent malaria in plants empir- hanimposa (figures 1; 2 and 3) is known as a plant used in ically used to treat malaria. There is also a need to generate the treatment of malaria. It can be used alone (see plant reliable scientific data to determine whether the plants list). The genus Zanthoxylum is used not only in the Anda- currently used to treat malaria are actually effective. In the sibe region (eastern part of Madagascar), but also in the long term, this should help to prevent deaths due to igno- western parts of Madagascar (Rabarison & Randri- rance and the misuse of plants for self-medication in the anarivelojosia, unpublished). We, therefore, decided to col- absence of advice from a qualified medical professional. lect and investigate Z. tsihanimposa. Plant material was collected from Ankarafantsika, in the wetter north-west- Materials and Methods ern part of Madagascar. The chemical extraction and anal- Ethnobotanical survey ysis were carried out at the University of Natal, Durban, We considered the traditional healers, known locally as South Africa in 2001. The crude hexane extract of the stem ombiasy, to be the best source of information for our study. bark of Z. tsihanimposa was fractionated by liquid chroma- Field work was carried out in August 1993 in and around tography over silica gel (Merck 9385) using a mixture of Andasibe (~130 km east of Antananarivo, the capital of various proportions of dichloromethane and methanol. Madagascar; 1,000 m above sea level). A retired forester Antimalarial in vitro tests were performed at the Institut introduced us to three local healers, aged between 53 and Pasteur de Madagascar. In vitro chemosensitivity tests were 89 years, all of good reputation in the area. Healers gave performed with the isotopic microtest method [9,10]. P. their consent. Drawing from the experience of Hammer falciparum FCM29 strain resistant to chloroquine but sus- and Johns [8], we interviewed these healers by means of ceptible to quinine – cultured in our laboratory according informal, unstructured conversations. We thought that to the method described by Trager and Jensen [11] – was open discussion, rather than a rigid questionnaire, would used to assess the antimalarial activity of the compounds provide the opportunity for healers to talk about their spe- tested. Quinine base (Sigma, St Louis, MO, USA) was cialties and experiences and to provide as much detail as tested as the reference antimalarial drug (figure 5). The they wished. This loose structure also eliminated the pres- antimalarial activity of the compound tested was sure to provide answers to rigid questions, which might expressed as the IC50 i.e. 50% inhibitory concentration [10]. Page 2 of 9 (page number not for citation purposes) Malaria Journal 2003, 2 http://www.malariajournal.com/content/2/1/25